The effect of biofeedback training on affective regulation and simulated car-racing performance: A multiple case study analysis     

William A. Edmonds  Gershon Tenenbaum  Derek T. Y. Mann  Michael Johnson  Akihito Kamata 《Journal of sports sciences》2013,31(7):761-773

Abstract

In this study, we wished to investigate the factors that determine the direction of the spin axis of a pitched baseball. Nineteen male baseball pitchers were recruited to pitch fastballs. The pitching motion was recorded with a three-dimensional motion analysis system (1000 Hz), and the orientations of the hand segment in a global coordinate system were calculated using Euler rotation angles. Reflective markers were attached to the ball, and the direction of the spin axis was calculated on the basis of their positional changes. The spin axis directions were significantly correlated with the orientations of the hand just before ball release. The ball is released from the fingertip and rotates on a plane that is formed by the palm and fingers; the spin axis of the ball is parallel to this plane. The lift force of the pitched baseball is largest when the angular and translational velocity vectors are mutually perpendicular. Furthermore, to increase the lift forces for the fastballs, the palm must face home plate.  相似文献   

Health benefits of Kung Fu: A systematic review     

Tracey Wai Man Tsang  Michael Kohn  Chin Moi Chow  Maria Fiatarone Singh 《Journal of sports sciences》2013,31(12):1249-1267

Abstract

The Chinese martial arts (Kung Fu) have existed for centuries and are generally accepted as being beneficial for health without much empirical data. The aim of this systematic review was to assess the health effects of “hard” Kung Fu styles by performing electronic and manual searches of the literature. The aspects of health and the Kung Fu style examined varied between most studies; in some cases, the martial art group consisted of practitioners of other martial art styles also. Of 2103 references identified, only nine papers were eligible and reviewed. All were observational studies, observing a range of health aspects possibly related to Kung Fu training or performance. Our findings suggest that there is no evidence that Kung Fu practice is associated with the prevention or treatment of any health condition. However, as a moderate- to high-intensity form of aerobic exercise, it may confer benefits similar to those attributed to other aerobic training modalities. However, this hypothesis remains to be tested in clinical trials. Physiological benefits (e.g., aerobic capacity and bone density) may be associated with long-term Kung Fu practice. Future research in this area should adopt experimental designs, clearly identifying eligibility criteria, testing and training protocols, and include health-related outcomes and documentation of adverse events, to advance knowledge in this field.  相似文献   

Velocity and acceleration before contact in the tackle during rugby union matches     

Sharief Hendricks  David Karpul  Fred Nicolls  Michael Lambert 《Journal of sports sciences》2013,31(12):1215-1224

Abstract

The velocity and acceleration at which the ball-carrier or tackler enters the tackle may contribute to winning the contest and prevailing injury free. Velocity and acceleration have been quantified in controlled settings, whereas in match-play it has been subjectively described. The purpose of this study was to determine the velocity and acceleration of the ball-carrier and tackler before contact during match-play in three competitions (Super 14, Varsity Cup, and Under-19 Currie Cup). Using a two-dimensional scaled version of the field, the velocity and acceleration of the ball-carrier and tackler were measured at every 0.1 s to contact for 0.5 s. For front-on tackles, a significant difference (P < 0.05) between the ball-carrier (4.6 ± 1 m · s^–1) and tackler (7.1 ± 3.5 m · s^–1) was found at the 0.5 s time to contact interval in the Varsity Cup. For side-on tackles, differences between the two opposing players were found at 0.5 s (ball-carrier: 4.6 ± 1.7 m · s^–1; tackler: 3.1 ± 1.2 m · s^–1) and 0.4 s (ball-carrier: 6.3 ± 2.3 m · s^–1; tackler: 3.7 ± 1.6 m · s^–1) at Under-19 level. After 0.4 s, no significant differences (P > 0.05) were evident. Also, the ball-carrier's velocity over the 0.5 s was relatively stable compared with that of the tackler. Results suggest that tacklers adjust their velocity to reach a suitable relative velocity before making contact with the ball-carrier.  相似文献   

The effects of eccentric phase duration on concentric outcomes in the back squat and bench press in well-trained males     

Joseph P. Carzoli  Colby A. Sousa  Daniel J. Belcher  Eric R. Helms  Andy V. Khamoui  Michael Whitehurst 《Journal of sports sciences》2013,31(23):2676-2684

ABSTRACT

The velocity and magnitude in which the eccentric phase of an exercise is completed directly affects performance during the concentric phase. Therefore, the purpose of this research was to investigate the effects of eccentric phase duration on concentric outcomes at 60% and 80% of one-repetition maximum (1RM) in the squat and bench press. Sixteen college-aged, resistance-trained males completed 1RM testing, established normative eccentric durations, and performed fast (0.75 times normative) and slow (2.0 times normative) metronome-controlled eccentric duration repetitions. Outcome measures assessed during the concentric phase were: average concentric velocity (ACV), peak concentric velocity (PCV), rating of perceived exertion (RPE), range of motion (ROM), and barbell path. Eccentric duration was significantly and inversely correlated with ACV at 60% (r = ?0.408, p = 0.004) and 80% (r = ?0.477, p = 0.001) of 1RM squat. At 60% of 1RM squat, both fast and slow eccentric conditions produced greater (p < 0.001) PCV than normative duration with fast also producing greater PCV than slow (p = 0.044). Eccentric duration had no impact on RPE, ROM, or barbell path. Our results report for the first time that resistance-trained males performing a deliberately faster eccentric phase may enhance their own squat and bench press performance.  相似文献   

Tackle and ruck technique proficiency within academy and senior club rugby union     

Steve den Hollander  Michael Lambert  Ben Jones  Sharief Hendricks 《Journal of sports sciences》2013,31(22):2578-2587

ABSTRACT

This study examined the validity of a tool that assesses tackle and ruck technique in training and established reference data for tackle, ball-carry and ruck technique at different levels of play in rugby union. One hundred and thirty-one amateur rugby union players; 37 senior, 51 first-grade academy and 43 second-grade academy players, participated in a two-on-two contact drill. The drill was filmed and the players’ tackle, ball-carry and ruck technique were assessed using standardized technical criteria. Senior level players scored significantly higher in all three assessments; tackle technique senior vs academy 1^st (p < 0.01, effect size (ES) = 0.7, moderate), senior vs academy 2^nd (p < 0.01, ES = 0.7, moderate); ball-carry technique senior vs academy 1^st (p < 0.01, ES = 0.6, moderate), senior vs academy 2^nd (p < 0.01, ES = 0.8, moderate); ruck technique senior vs academy 1^st (p < 0.01, ES = 0.7, moderate), senior vs academy 2^nd (p < 0.01, ES = 0.4, small). These findings emphasize the importance of developing contact technique to allow players to progress to higher levels, and provide validity to an assessment tool which can facilitate this process.  相似文献   

Throwing performance in water polo is related to in-water shoulder proprioception     

Andrea H. Hams  Kerrie Evans  Roger Adams  Gordon Waddington  Jeremy Witchalls 《Journal of sports sciences》2013,31(22):2588-2595

ABSTRACT

Water polo players require a high level of upper-extremity strength, flexibility and coordination to achieve a peak level of throwing performance. Increased levels of shoulder proprioceptive acuity, strength and range of motion (ROM) have been previously associated with higher sporting performance. A coach-rating scale, used to quantify an athlete’s kicking proficiency in soccer; was adapted in the current study to measure each coach’s subjective expert opinion regarding athletes’ throwing mechanics, velocity, and accuracy. To examine this hypothesis shoulder proprioception acuity of 18 water polo players was measured both in-water and on-land using an AMEDA apparatus and correlated with coach-rated throwing performance and clinical measures of shoulder strength and ROM. There was a moderate positive correlation between the in-water and the on-land proprioception acuity (r = 0.47, p < 0.05). The in-water score showing a strong positive correlation with coach rated throwing mechanics (r = 0.68, p < 0.05) and velocity (r = 0.75, p = 0.02), suggesting that superior proprioception acuity contributed to fast, mechanically-efficient throwing. These findings support the notion that in-water proprioceptive acuity is an important determinant of the throwing performance achieved by water polo athletes and its measurement may be a valuable adjunct to current athlete screening.  相似文献   

Gold Medal Volleyball: The Training Program and Physiological Profile of the 1984 Olympic Champions     

Carl M. McGown  Robert K. Conlee  Anthony A. Sucec  Michael J. Buono    William Phillips 《Research quarterly for exercise and sport》2013,84(2):196-200

Abstract

This study focused on the differences between experienced and inexperienced physical education teachers' approaches to planning, low inference indicators of teaching behavior during instruction, and global variables from the Beginning Teacher Evaluation Study. It was found experienced teachers asked many more questions before they began planning than did inexperienced teachers. Experienced teachers' plans reflected a concern about contingencies that might arise during instruction, whereas inexperienced teachers' plans did not. Interaction analysis and codings of student engagement showed marked differences between experienced and inexperienced teachers. Judging the qualities of experienced and inexperienced teachers also showed important differences. These sources of data are interrelated and give a vivid picture of how experienced and inexperienced teachers differ in accomplishment of instruction. The findings are discussed in terms of what they may mean for teacher development programs.  相似文献   

Programming Time as a Function of Movement Constraint     

Andrew M. Gordon  Robert W. Christina 《Research quarterly for exercise and sport》2013,84(1):92-97

Abstract

Although the benefits of exercise are well documented, an international problem of physical inactivity exists. More research, especially theory based, has been recommended. One promising approach for studying exercise behavior is that proposed in the Transtheoretical Model (TTM) of behavior change. This model, however, has received minimal cross-cultural attention and, relative to the current study, measurement instruments have only recently been translated into the Finnish language. The purpose of this study was to assess American and Finnish college students' exercise behaviors on the basis of TTM. Participants were American (n = 169) and Finnish (n = 168) college students who completed language-specific measures of exercise behavior, stage of change, processes of change, decisional balance, self-efficacy, and temptation. The only cultural difference observed was that the American participants rated themselves higher on barrier self-efficacy relative to the Finnish participants. Regardless of nationality or gender, participants classified by their stage of change differed on all the core constructs assessed. These results generally support the utility of TTM for understanding American and Finnish college students' exercise behavior.  相似文献   

Coach Autonomy Support,Basic Need Satisfaction,and Intrinsic Motivation of Paralympic Athletes     

Hailey R. Banack  Catherine M. Sabiston  Gordon A. Bloom 《Research quarterly for exercise and sport》2013,84(4):722-730

The purpose of the present study, grounded in self-determination theory, was to explore the relationship between Paralympic athletes' perceptions of autonomy-supportive coach behavior, basic psychological needs, and intrinsic motivation to know, accomplish, and experience stimulation. One hundred thirteen Canadian Paralympic athletes completed an online survey, consisting of measures of coach autonomy support; of perceptions of autonomy, competence, and relatedness; and of intrinsic motivation. Perceived coach autonomy support was a predictor of athletes' perceptions of autonomy and relatedness. Perceived competence was a significant predictor of all three forms of intrinsic motivation, while perceived autonomy was a significant predictor of intrinsic motivation to accomplish and experience stimulation. The results highlight the important relationship between coach behavior and athlete motivation in disability sport.  相似文献   

Effects of Different Durations of Physical Training on Cardiorespiratory Function,Body Composition,and Serum Lipids     

Chris A. Milesis  Michael L. Pollock  Michael D. Bah  John J. Ayres  Ann Ward  A. C. Linnerud 《Research quarterly for exercise and sport》2013,84(4):716-725

Abstract

The purpose of the study was to determine the effects of 15, 30, and 45 min of conditioning on maximum performance and cardiorespiratory fitness variables, body composition, pulmonary function, and serum lipids. Subjects, ages 20 to 35, were 59 inmates at a California state prison. The conditioning included running and walking and was performed three days/week at approximately 85 to 90% max HR for 20 weeks. The distance covered per exercise session was approximately 1.75, 3.25, and 5.1 miles for the 15-, 30-, and 45-min groups, respectively.

Improvements in treadmill performance time. [Vdot]O₂ max, max O₂ pulse, diastolic blood pressure, and total skinfold fat were proportional to duration of the training session; i.e., the subjects training in the longer duration sessions showed the greater improvements. The control group showed no significant change during the same period. Compared to the control group, the 15-min group made significant reductions in resting HR, total skinfold fat, percent fat, and waist girth and increases in [Vdot]O₂ max, max O₂ pulse,[Vdot]_E max, and treadmill performance time. Vital capacity, FEV_1.0, and % FEV_1.0 remained relatively unchanged in all four groups, as did serum cholesterol and triglycerides. The 45-min group improved significantly more than the 15-min group in treadmill time, [Vdot]O₂ max, max O₂ pulse, resting systolic and diastolic blood pressures, and percent fat. In general, comparisons between the 15- and 30-min groups and between the 30- and 45-min groups failed to yield statistically significant differences.  相似文献